Upstream oodles of Chrome for Android code into Chromium.

chrome/android/java_staging/src/org/chromium/chrome/browser/tabmodel/TabWindowManager.java

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.tabmodel;
+
+import android.app.Activity;
+
+import org.chromium.base.ActivityState;
+import org.chromium.base.ApplicationStatus;
+import org.chromium.base.ApplicationStatus.ActivityStateListener;
+import org.chromium.base.ThreadUtils;
+import org.chromium.base.VisibleForTesting;
+import org.chromium.chrome.browser.ChromeActivity;
+import org.chromium.ui.base.WindowAndroid;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Manages multiple {@link TabModelSelector} instances, each owned by different {@link Activity}s.
+ */
+public class TabWindowManager implements ActivityStateListener {
+    /**
+     * An index that represents the invalid state (i.e. when the window wasn't found in the list.
+     */
+    public static final int INVALID_WINDOW_INDEX = -1;
+
+    /** The maximum number of simultaneous TabModelSelector instances in this Application. */
+    @VisibleForTesting
+    public static final int MAX_SIMULTANEOUS_SELECTORS = 3;
+
+    /**
+     * A factory interface for building a {@link TabModelSelector} instance.
+     */
+    public interface TabModelSelectorFactory {
+        /**
+         * Builds a {@link TabModelSelector}.
+         * @param activity      A {@link ChromeActivity} instance.
+         * @param windowAndroid A {@link WindowAndroid} instance that should connect to
+         *                      {@code activity}.
+         * @param selectorIndex The index of the {@link TabModelSelector}.
+         * @return              A new {@link TabModelSelector} instance.
+         */
+        TabModelSelector buildSelector(ChromeActivity activity, WindowAndroid windowAndroid,
+                int selectorIndex);
+    }
+
+    /** The singleton reference. */
+    private static TabWindowManager sInstance;
+
+    private TabModelSelectorFactory mSelectorFactory = new DefaultTabModelSelectorFactory();
+
+    private List<TabModelSelector> mSelectors = new ArrayList<TabModelSelector>();
+
+    private Map<Activity, TabModelSelector> mAssignments =
+            new HashMap<Activity, TabModelSelector>();
+
+    /**
+     * @return The singleton instance of {@link TabWindowManager}.
+     */
+    public static TabWindowManager getInstance() {
+        ThreadUtils.assertOnUiThread();
+        if (sInstance == null) sInstance = new TabWindowManager();
+        return sInstance;
+    }
+
+    /**
+     * Called to request a {@link TabModelSelector} based on {@code index}.  Note that the
+     * {@link TabModelSelector} returned might not actually be the one related to {@code index}
+     * and {@link #getIndexForWindow(Activity)} should be called to grab the actual index if
+     * required.
+     * @param activity An instance of {@link ChromeActivity}.  Must be the same {@link Activity} as
+     *                 the one referenced by {@code window}.
+     * @param window   A {@link WindowAndroid} as an instance.  The {@link TabModelSelector} that is
+     *                 created is bound to the {@link Activity} stored inside this window.
+     * @param index    The index of the requested {@link TabModelSelector}.  Not guaranteed to be
+     *                 the index of the {@link TabModelSelector} returned.
+     * @return         A {@link TabModelSelector} index, or {@code null} if there are too many
+     *                 {@link TabModelSelector}s already built.
+     */
+    public TabModelSelector requestSelector(ChromeActivity activity, WindowAndroid window,
+            int index) {
+        if (mAssignments.get(activity) != null) {
+            return mAssignments.get(activity);
+        }
+
+        if (index < 0 || index >= mSelectors.size()) index = 0;
+
+        if (mSelectors.get(index) != null) {
+            for (int i = 0; i < mSelectors.size(); i++) {
+                if (mSelectors.get(i) == null) {
+                    index = i;
+                    break;
+                }
+            }
+        }
+
+        // Too many activities going at once.
+        if (mSelectors.get(index) != null) return null;
+
+        TabModelSelector selector = mSelectorFactory.buildSelector(activity, window, index);
+        mSelectors.set(index, selector);
+        mAssignments.put(activity, selector);
+
+        return selector;
+    }
+
+    /**
+     * Finds the current index of the {@link TabModelSelector} bound to {@code window}.
+     * @param activity The {@link Activity} to find the index of the {@link TabModelSelector}
+     *                 for.  This uses the underlying {@link Activity} stored in the
+     *                 {@link WindowAndroid}.
+     * @return         The index of the {@link TabModelSelector} or {@link #INVALID_WINDOW_INDEX} if
+     *                 not found.
+     */
+    public int getIndexForWindow(Activity activity) {
+        if (activity == null) return INVALID_WINDOW_INDEX;
+        TabModelSelector selector = mAssignments.get(activity);
+        if (selector == null) return INVALID_WINDOW_INDEX;
+        int index = mSelectors.indexOf(selector);
+        return index == -1 ? INVALID_WINDOW_INDEX : index;
+    }
+
+    /**
+     * @return The number of {@link TabModelSelector}s currently assigned to {@link Activity}s.
+     */
+    public int getNumberOfAssignedTabModelSelectors() {
+        return mAssignments.size();
+    }
+
+    /**
+     * @return The total number of incognito tabs across all tab model selectors.
+     */
+    public int getIncognitoTabCount() {
+        int count = 0;
+        for (int i = 0; i < mSelectors.size(); i++) {
+            if (mSelectors.get(i) != null) {
+                count += mSelectors.get(i).getModel(true).getCount();
+            }
+        }
+        return count;
+    }
+
+    @Override
+    public void onActivityStateChange(Activity activity, int newState) {
+        if (newState == ActivityState.DESTROYED && mAssignments.containsKey(activity)) {
+            int index = mSelectors.indexOf(mAssignments.remove(activity));
+            if (index >= 0) mSelectors.set(index, null);
+            // TODO(dtrainor): Move TabModelSelector#destroy() calls here.
+        }
+    }
+
+    /**
+     * Allows overriding the default {@link TabModelSelectorFactory} with another one.  Typically
+     * for testing.
+     * @param factory A {@link TabModelSelectorFactory} instance.
+     */
+    @VisibleForTesting
+    public void setTabModelSelectorFactory(TabModelSelectorFactory factory) {
+        mSelectorFactory = factory;
+    }
+
+    private TabWindowManager() {
+        ApplicationStatus.registerStateListenerForAllActivities(this);
+
+        for (int i = 0; i < MAX_SIMULTANEOUS_SELECTORS; i++) mSelectors.add(null);
+    }
+
+    private static class DefaultTabModelSelectorFactory implements TabModelSelectorFactory {
+        @Override
+        public TabModelSelector buildSelector(ChromeActivity activity, WindowAndroid windowAndroid,
+                int selectorIndex) {
+            assert activity == windowAndroid.getActivity().get();
+            return new TabModelSelectorImpl(activity, selectorIndex, windowAndroid);
+        }
+    }
+}